Types of Arrays
 Arrays are of different types.
 They are
 One dimensional array
 Two dimensional array
 Multi dimensional array
One dimensional Array
 This array type is the simplest format among the arrays
 The array is given a name and its elements are referred to by their subscript or index.
 An array must be defined before it can be used to store the information.
 General format for one dimensional array
Type array_name[size]; 
Type  datatype
Array_name  name of the array
Size  index value
 For example
int students[50]; 
Note:  Single dimensional array is also called as one dimensional array. Array element should always be an integer value. 
Program
#include<iostream.h> void main() { double price[20], sum, avg, prod; sum = avg = 0; prod =1; for(int i=0;i<20;++i) { cout <<"enter price for the item"<<i+1<<":"; cin >>price[i]; sum+=price[i]; prod+=price[i]; } avg=sum/20; cout<<"sum"<<sum<<endl; cout<<"product="<<prod<<endl; cout<<"average="<<avg<<endl; } 
Two dimensional Arrays
 Two dimensional are a little complicated to use than one dimensional array.
 It is defined in the same manner as one dimensional array except that a separate pair of square brackets is required for each subscript.
 A 2D array can be used to store multiple numbers.
 It is mainly used in matrix calculation.
 The general format is
Type array_name [row][column]; 
 For example
int student[10][20]; 
0 
1 
2 
3 

0 
[0][0] 
[0][1] 
[0][2] 
[0][3] 
1 
[1][0] 
[1][1] 
[1][2] 
[1][3] 
2 
[2][0] 
[2][1] 
[2][2] 
[2][3] 
3 
[3][0] 
[3][1] 
[3][2] 
[3][3] 
4 
[4][0] 
[4][1] 
[4][2] 
[4][3] 

Initializing an array in two dimension
Where a[0][0]=1, a[1][1]=2 and so on...
Program
#include<iostream.h>
Void main() { int n[5][5]; int row,col; for(row=0;row<5;row++) { for(col=0;col<5;col++) { cout<<"enter the value of row["<<row+1<<"]col["<<col+1<<"]";cin>>n[row][col]; } } cout<<" the given array values are "<<endl; for(row=0;row<5;row++) for(col=0;col<5;col++) cout<<"the value of row["<<row+1<<"]col["<<col+1<<"]"<<n[row][col]<<endl1; } 
Multidimensional Array

C++ allows storing more than two elements in the array.

This type of array is called as multidimensional array.

The general format of multidimensional array is
Type array_name[a][a1][a2]............a[n]; 
 For example
int matrix[10][10][10]; 
 Hence it stores the value in the 3 X 3 matrix format.
Note: A matrix with one row(column) may be viewed as a vector and similarly a vector may be viewed as a matrix with one row(column) 